Mt Redoubt - Alaska

Alaska is graced with some of the most beautiful mountains in North America.

Mt Redoubt is in the Aleutian Mountain Range of Southern Alaska, in the Lake Clark National Park and Reserve. It is also the highest within the range. It is located about 100 miles South-West of Anchorage, and depending on how the wind blows, often is the first major city to get the ash fallout from an erupting volcano. Mt Redoubt is also known as a stratovolcano, which are the most picturesque and the most deadly of the volcano types. It is also near one of the busiest waterways in North America. It is from this waterway that ships and oil tankers going to and from Anchorage carries the Alaskan crude to the lower 48 states. But the most dangerous area is in the air. Mt Redoubt is also in the middle of one of the busiest air travel routes in the country, both local and the big jets.

Mt Redoubt is about 9,000 to 11,000 ft high, and about 10 km around its base. It is made up of pilaster flow deposits and lava flows on what is called the Mesozoic era rocks. The Northern side is where the current vent is located, by the Drift Glacier. Also a Holocene lahars deposit can travel as far as Cook Inlet.

The Aleutian chain make up the Northern part of the 'Ring of Fire' There are about 40 active volcanoes in Alaska, most are in this chain of mountains. The Ring of Fire area is the ost volcanically and seismically active regions in the world. The most common activity is on the coasts of North and South America and along Japan. More than 75% of the world's volcano's lie in The Ring of Fire.

Scientist have learned that certain kinds of magma that have a lot of silica are viscous, which is warm and have a gooey-taffy like texture. These trap the gases so that the only way for it to escape is for the magma to reach the top and explodes through the earth's crust, much like a shaken can of pop does when you open it.

Mt Redoubt has erupted before. In 1902, 1966, and in 1989. With the '89' eruption, she blew ash as high as 45,000 ft into the air, and kept erupting for months afterwards. Mt Redoubt has been on a Watch Alert Orange since mid-January. Alaskan volcanoes differ from Hawaiian volcanoes in that Alaskan normally just have the gas exploding up and out, creating a plume of ash of glass and rock. The Hawaiian volcanoes have the hot slow moving ooze running out.

Sources:

National Geographic Pictures

Webcams from the Alaska Volcano Observatory

The Volcanism Blog